Tuesday, October 25, 2005

Flu Facts

Bogdan Cristel
With widespread interest in avian influenza or “bird flu”, Audubon is providing the following information and links as a resource for those who may be concerned about avian influenza, as well as about how birds are involved. Also included are some general precautions for protecting both human and bird health.

Background on Avian Flu
There are over 135 different strains of avian influenza virus. Most strains circulate in low levels within wild bird populations. Though they usually cause only mild illness in wild birds, some strains may cause lethal outbreaks in domestic poultry. A few avian influenza strains are more virulent, and can cause high mortality in both wild birds and poultry stocks.

Most avian influenza strains do not normally infect species other than birds, though a few subtypes can be transmitted from birds to humans. Avian influenza viruses become much more dangerous if they mutate to allow easy transmission from one human to another, not just from birds to humans. The most devastating avian influenza epidemic occurred in 1918 when a highly pathogenic strain of avian influenza mutated allowing people to infect other people. An estimated 40 to 50 million people died worldwide as a result.

The Current Strain of Avian Influenza: H5N1
Since 1997, the H5N1 strain of highly pathogenic avian influenza (HPAI) has infected over 100 people and caused at least 65 deaths in East and Southeast Asia. While any human infection is cause for concern and action, this current avian flu outbreak has affected a relatively small number of people, and has very limited ability to be transmitted from person to person. Rather, the virus appears to be transmitted to humans through consumption of or direct contact with infected poultry or contaminated surfaces. Over one million domestic birds have been culled to contain outbreaks. There is no evidence that the virus has mutated to spread widely from person to person.

Do Wild Birds Transmit H5N1 to People?
In the summer of 2005, the virus spread to Central Asia and China where it was detected in both domestic birds and wild birds. These outbreaks do not indicate that wild birds are effective carriers or reservoirs for the H5N1 virus. The virus is so virulent that it appears to be self-limiting; infected wild birds die before they can travel far or transmit the virus to many other birds.

Leading experts including the World Health Organization, Food and Agricultural Organization of the United Nations, and World Organization for Animal Health all emphasize that culling wild bird populations is highly unlikely to stop the spread of the disease, and would only divert resources away from more important disease control measures.

(See statements by UN Food and Agricultural Organization)

Has H5N1 Been Found in North America?
The H5N1 avian influenza virus has not been found in wild birds in North America. There is a remote chance that infected wild birds from Asia could bring the virus with them during fall migration to North America. The US Fish and Wildlife Service, US Geological Survey (USGS), Alaska Department of Fish & Game, and public health agencies are working together to test thousands of waterfowl and shorebirds for the virus in Alaska, and field sampling is being integrated with surveillance programs throughout the United States and Canada.

What You Can Do
1) While the possibility of contracting the H5N1 virus from wild birds is very unlikely, people who have close personal contact with wild birds should take measures to protect themselves by practicing animal handling and sanitary practices recommended by the USGS National Wildlife Health Center Wildlife Health Bulletin #05-03.

2) People who feed birds are not at high risk of contracting avian influenza from birds in their yards or at their feeders. However, since birds can transmit other diseases to humans (e.g. salmonellosis), people who feed birds should routinely clean their feeders and bird baths as recommended by Audubon and the USGS National Wildlife Health Center. People who come into contact with wild bird excreta should thoroughly clean up with soap and water.

Additional Resources
*Centers for Disease Control
*United Nations Food and Agricultural Organization
*USGS National Wildlife Health Center
*BirdLife International Statement on Avian Influenza
*Wetlands International Statement on Avian Influenza
*NPR Bird Flu in Depth
*Latest News from Google News